The present invention relates in general to a secondary air supply system which is constructed to supply air into an exhaust conduit system of an internal combustion engine for completely burning the remaining unburned combustible compounds, such as hydrocarbons (HC) and carbon monoxide (CO), contained in the exhaust gases emitted from the engine, and more particularly to a so called reed valve device which is employed in the secondary air supply system for promoting the admission of air into the exhaust conduit system of the engine by the pulsations of the exhaust gases passing through the conduit system.
In a reed valve device employed in the secondary air supply system, it is very necessary not only to minimize the air-flow resistance of the device for increasing the flow rate of air into the exhaust conduit system but also to tightly seal the device for completely preventing exhaust gas leaks into the open air. Furthermore, it is necessary to avoid the unpleasant chattering phenomenon caused by vibrations of the reed proper of the device.
In a conventional reed valve device, however, it has been observed that the connection of the reed valve device to its casing is made in such manner that a base on which the reed proper is mounted is directly connected to the casing by means of bolts. In this connecting method, there exists a possibility of warping of the base of the device as the bolts are screwed for connecting the same to the casing. This warping will cause the above-mentioned leaks of the heated exhaust gases into the open air. Furthermore, under this connecting condition, there will also occur a problem that the vibrations of the reed proper are directly transmitted to the casing of the reed valve device through the bolts thus causing the unpleasant noises.